Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rafaelctt on August 21, 2022, 07:14:33 am
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Hello, can you guide me on a 5w amp scheme to which you can insert a reverb with a 9" tank approximately. Thank you!
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The first that quickly comes in my mind now are
Gibson GA 1RT 1
https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_1rt_1.pdf (https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_1rt_1.pdf)
(https://i.imgur.com/ulpHTxW.png)
Gibson GA 1RVT
https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_1rvt.pdf (https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_1rvt.pdf)
(https://i.imgur.com/yxk1Tcy.png)
BTW Also exist some Champ Reverb amp but those are custom build by passionates
See here
https://el34world.com/Forum/index.php?topic=23328.0 (https://el34world.com/Forum/index.php?topic=23328.0)
Franco
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when i'm wanting "ideas", I ALWAYS start here;
Tube amp Schematics Index Page (el34world.com) (https://el34world.com/charts/TubeAmpSchematics.htm)
beware, if you like this sport, you may need to limit your exposure, that page can become addictive :icon_biggrin:
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when i'm wanting "ideas", I ALWAYS start here;
Tube amp Schematics Index Page (el34world.com)
don't know why this image appeared on my mind :icon_biggrin:
(https://i.imgur.com/J9bk9M2.jpg)
:bump1:
Franco
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:laugh:
that's my brain most mornings, by nighttime i've plowed a giant hole through the maze, just to realize i'm back where I started :headbang:
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Do you think that such a combination could work? Logically studying changes in resistance values mainly.
(https://i.postimg.cc/Yqp1mJRJ/composici-n-de-esquemas-para-5w.jpg)
It would be the combination of Fender Pricenton preamp and reverb and Vox Ac4 power amp and source
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Probably need to include the next gain stage from the PR.
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Those on the link I posted Is a proven schem & layout
https://el34world.com/Forum/index.php?topic=23328.0
Franco
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I can't get into that forum(ampgarage) as a member. I've tried repeatedly to register, but I can't. Does this information exist elsewhere?
Thank you
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I can't get into that forum(ampgarage) as a member. I've tried repeatedly to register, but I can't. Does this information exist elsewhere?
Thank you
All the links in this post seem to be EL34 world open source or did I miss something? Can't see any ampgarage links.
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The ampgarage link Is on the thread i linked, however schematic and layout are on the link I posted
Franco
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The ampgarage link Is on the thread i linked, however schematic and layout are on the link I posted
Franco
grazie :smiley:
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I can't get into that forum(ampgarage) as a member. I've tried repeatedly to register, but I can't.
OK, try to conctact an Ampgarage administrator to solve the registration problems
currently read the whole thread on the attached .pdf
Franco
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I can't get into that forum(ampgarage) as a member. I've tried repeatedly to register, but I can't.
Did you read the FAQs?
I sent the administrator a message about this. I'll let you know what he says.
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I can't get into that forum(ampgarage) as a member. I've tried repeatedly to register, but I can't.
TAG administrator has set up your account. Here's what he said... "I've activated his account, he's got a gmail account and it seems like due to the messed up state with email on this forum, gmail especially deletes/discards all forum mail. It doesn't even end up in the spam folder so I've been told."
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I understand then that I will have to register with an email that is not gmail?
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I understand then that I will have to register with an email that is not gmail?
No. You missed the important part. He has activated your account. I think that means you just need to log in with your name/password.
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See if this works
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I built three of these into combo cabinets. See attached - 2 are KT88 versions, the third is a 6L6GC, the schematic attached is to the 6L6GC model. One is a gift for this coming x-mas, the second is mine, the third was promised but individual fell on hard times, so no home for it yet. The KT88 amp pair are driving a JBL D130, and the 6L6GC model (gift amp) is driving a pair of 10" Eminence Red Coat.
The classictone 40-18031 & Allen TO-11A are obviously no longer available, Amp Parts Direct were selling a Heyboer clone of the 40-18031 part, but are sold out now - No telling when or if that part will return. I tested the Musical Power Supplies 12VA SE and it performed well, however, the Allen TO-11A IMO is/was the best sounding overall. The reverb driver I used originally was the Classictone 40-18030 - I replaced that with the Hammond 1750AX with like results. I had several PCB manufactured. Some component changes on the PCB, OT and PT swaps are all that differ from the KT88 and 6L6GC models.
https://www.hammfg.com/files/parts/pdf/1750AX.pdf
https://www.ebay.com/itm/155092204102?hash=item241c373a46:g:LQIAAOSwMXxfjmJ9
https://shop.amppartsdirect.com/collections/apd-custom-by-heyboer/products/fender-champ-style-15w-upgrade-single-ended-4-8-16-ohm-output-transformers-apd-8031h-by-heyboer-transformers-replaced-40-18031
https://www.dropbox.com/s/8xkixymj9k5te2e/20210805_215745.jpg?dl=0
https://www.dropbox.com/s/703a9sep6shwmas/20210805_220435.jpg?dl=0
https://www.dropbox.com/s/u90hfs5ijoj29qa/20201213_162046.jpg?dl=0
https://www.dropbox.com/s/3e658619uvpciqb/20210714_145758.jpg?dl=0
https://www.dropbox.com/s/ocgfrc9yjun10ko/20210712_193614.jpg?dl=0
--Pete
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I understand then that I will have to register with an email that is not gmail?
No. You missed the important part. He has activated your account. I think that means you just need to log in with your name/password.
I have got it!! Thank you!!
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I built three of these into combo cabinets. See attached - 2 are KT88 versions, the third is a 6L6GC, the schematic attached is to the 6L6GC model. One is a gift for this coming x-mas, the second is mine, the third was promised but individual fell on hard times, so no home for it yet. The KT88 amp pair are driving a JBL D130, and the 6L6GC model (gift amp) is driving a pair of 10" Eminence Red Coat.
The classictone 40-18031 & Allen TO-11A are obviously no longer available, Amp Parts Direct were selling a Heyboer clone of the 40-18031 part, but are sold out now - No telling when or if that part will return. I tested the Musical Power Supplies 12VA SE and it performed well, however, the Allen TO-11A IMO is/was the best sounding overall. The reverb driver I used originally was the Classictone 40-18030 - I replaced that with the Hammond 1750AX with like results. I had several PCB manufactured. Some component changes on the PCB, OT and PT swaps are all that differ from the KT88 and 6L6GC models.
https://www.hammfg.com/files/parts/pdf/1750AX.pdf
https://www.ebay.com/itm/155092204102?hash=item241c373a46:g:LQIAAOSwMXxfjmJ9
https://shop.amppartsdirect.com/collections/apd-custom-by-heyboer/products/fender-champ-style-15w-upgrade-single-ended-4-8-16-ohm-output-transformers-apd-8031h-by-heyboer-transformers-replaced-40-18031
https://www.dropbox.com/s/8xkixymj9k5te2e/20210805_215745.jpg?dl=0
https://www.dropbox.com/s/703a9sep6shwmas/20210805_220435.jpg?dl=0
https://www.dropbox.com/s/u90hfs5ijoj29qa/20201213_162046.jpg?dl=0
https://www.dropbox.com/s/3e658619uvpciqb/20210714_145758.jpg?dl=0
https://www.dropbox.com/s/ocgfrc9yjun10ko/20210712_193614.jpg?dl=0
--Pete
My idea is to use semiconductors in rectification (diodes), EL84 as power and short reverb tank.
What PT do you use in this amp?
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I wish someone guided me on a 5W amp with reverb but despite good efforts, build a 5w amp and a reverb unit is all they could do. Am still thankfull, though.
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I built three of these into combo cabinets. See attached - 2 are KT88 versions, the third is a 6L6GC, the schematic attached is to the 6L6GC model. One is a gift for this coming x-mas, the second is mine, the third was promised but individual fell on hard times, so no home for it yet. The KT88 amp pair are driving a JBL D130, and the 6L6GC model (gift amp) is driving a pair of 10" Eminence Red Coat.
The classictone 40-18031 & Allen TO-11A are obviously no longer available, Amp Parts Direct were selling a Heyboer clone of the 40-18031 part, but are sold out now - No telling when or if that part will return. I tested the Musical Power Supplies 12VA SE and it performed well, however, the Allen TO-11A IMO is/was the best sounding overall. The reverb driver I used originally was the Classictone 40-18030 - I replaced that with the Hammond 1750AX with like results. I had several PCB manufactured. Some component changes on the PCB, OT and PT swaps are all that differ from the KT88 and 6L6GC models.
https://www.hammfg.com/files/parts/pdf/1750AX.pdf (https://www.hammfg.com/files/parts/pdf/1750AX.pdf)
https://www.ebay.com/itm/155092204102?hash=item241c373a46:g:LQIAAOSwMXxfjmJ9 (https://www.ebay.com/itm/155092204102?hash=item241c373a46:g:LQIAAOSwMXxfjmJ9)
https://shop.amppartsdirect.com/collections/apd-custom-by-heyboer/products/fender-champ-style-15w-upgrade-single-ended-4-8-16-ohm-output-transformers-apd-8031h-by-heyboer-transformers-replaced-40-18031 (https://shop.amppartsdirect.com/collections/apd-custom-by-heyboer/products/fender-champ-style-15w-upgrade-single-ended-4-8-16-ohm-output-transformers-apd-8031h-by-heyboer-transformers-replaced-40-18031)
https://www.dropbox.com/s/8xkixymj9k5te2e/20210805_215745.jpg?dl=0 (https://www.dropbox.com/s/8xkixymj9k5te2e/20210805_215745.jpg?dl=0)
https://www.dropbox.com/s/703a9sep6shwmas/20210805_220435.jpg?dl=0 (https://www.dropbox.com/s/703a9sep6shwmas/20210805_220435.jpg?dl=0)
https://www.dropbox.com/s/u90hfs5ijoj29qa/20201213_162046.jpg?dl=0 (https://www.dropbox.com/s/u90hfs5ijoj29qa/20201213_162046.jpg?dl=0)
https://www.dropbox.com/s/3e658619uvpciqb/20210714_145758.jpg?dl=0 (https://www.dropbox.com/s/3e658619uvpciqb/20210714_145758.jpg?dl=0)
https://www.dropbox.com/s/ocgfrc9yjun10ko/20210712_193614.jpg?dl=0 (https://www.dropbox.com/s/ocgfrc9yjun10ko/20210712_193614.jpg?dl=0)
--Pete
My idea is to use semiconductors in rectification (diodes), EL84 as power and short reverb tank.
What PT do you use in this amp?
PT make and model # noted in schematic. Hammond 272BX
--pete
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For my area it should be 240v and 50 hz. I have thought about the hammond 290UEX. Do you think it would work?
https://www.tube-town.net/ttstore/hammond-290uex-for-fender-power-hot-rod-deluxe.html
O
https://www.tube-town.net/ttstore/hammond-290bex-for-fender-power-125p23d-041316-deluxe.html
O
https://www.tube-town.net/ttstore/hammond-291aex-for-fender-power-125p1b-022772-upgrade-champ.html
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The 290UEX would work but it's overkill for a 5 watt amp. I would rather use the 291AEX.
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I think I'll do that build, with those components. Do you think it could work well? Can I replace the choke with a resistor? Can I replace the rectification valve with diodes? Thank you
(https://i.postimg.cc/ZYXgjbcc/composicion-V2.jpg)
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Do you think it could work well? Yes. May need a little tweaking. I would use an 8AB3C1B tank.
Can I replace the choke with a resistor? yes
Can I replace the rectification valve with diodes? yes
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Instead of a choke you can use a resistor
or, a gyrator (that is similar to an inductor)
Franco
From Mr. Merlin
(You can find a lot of interesting things on Merlin's Brooks)
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Could this scheme be definitive? What diodes do you recommend?
(https://i.postimg.cc/FF2sK3Qm/composicion-V3.jpg)
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1N4007 diodes and Hoffman sells them.
325 x 1.4 = 455 volts I think with solid state rectification you may get more than 420v on node A on the B+ rail? My guess is that it will be higher than 420v?
420/1.4 = 300 volts If you only want 420v on node A, you may wish to use a PT that is closer to 300-0-300 instead of 325-0-325?
OR use a GZ34 325 x 1.3 = 423v
With respect, Tubenit
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Thank you!!
I have tried to use the same transformer as the one from Fender Pricenton. Do you know of a 300+300 (primary 240V) transformer model for a 5w amp with reverb?
I could maybe use a resistor between switch and B+A to drop those 20 volts.
20/100mA: 200 Ohm approximately. Would it work?
https://www.tube-town.net/ttstore/hammond-372bx.html
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Do you think this transformer would be better?
https://www.tube-town.net/ttstore/hammond-372bx.html
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Do you think this transformer would be better?
https://www.tube-town.net/ttstore/hammond-372bx.html (https://www.tube-town.net/ttstore/hammond-372bx.html)
Yes.
--Pete
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Just to add a bit more confusion - with options
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Just to add a bit more confusion - with options
Thanks. I intend to do an "All in one".
A small amp (300x300x200mm) in which it has 5w, reverb, distortion, tone control and an output switch for 5-3-1.5w. That's why I look for components that take up little space.
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The distortion (as an effect) in these amps with gain and master control (in the first stage and before the final stage)?
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Once my first tube amp is done, we'll start on the second.
I have added two modifications (middle tone and master volume) do you think they can really be used to optimize this amp?
(https://i.postimg.cc/7hwDH0jF/composicion-V3.jpg)
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imho the master volume on a 5W amp is redundant
you have a volume on the guitar, you have a gain knob on the amp, one more pot will not be impressive.
most guitarist that played through my 5W'rs set the gain, then use the guitar to roll up and down the loud
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That Vox attnuator circuit should make a MV pot useless.
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I TOTALLY AGREE WITH YOU. My idea is not to reduce power.
What I want is to be able to give very little gain in the Master and a lot in the Gain with the idea of creating a distortion.
40 years ago I did it on some solid state amp designs of mine and it worked.
But in valves it is the second montage that I do and I wanted to experiment.
Can distortion be achieved this way?
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The 0.002uFd and 200k pot at the 6V6 grid cuts below 380Hz. 13dB down on your low note. That sounds pretty gut-less, no?
There's three gain stages and two loss networks. As I figure it, there's just-barely enough gain to distort the 3rd stage with small plucks. No gross distortion.
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The 0.002uFd and 200k pot at the 6V6 grid cuts below 380Hz. 13dB down on your low note. That sounds pretty gut-less, no?
There's three gain stages and two loss networks. As I figure it, there's just-barely enough gain to distort the 3rd stage with small plucks. No gross distortion.
Well, that's the problem. What would be the proposed solution?
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build the TS into the circuit, but don't wire it in, instead use a coupler cap to the gain pot top and the wiper feeds the next stage. Your guitar will be the TS for testing.
the magic number I use in a self-biased amp is the Vk (cathode vdc). I want my drive AC signal >Vk, maybe up to twice. Then I'll tame it as required.
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Thank you!!
I understand that I should lower the Vk below the guitar signal to have distortion?
Would I have to lower the value of the Rk (1k5)?
Do you have a schematic please?
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Vk is your BIAS, set it for proper tube power with NO signal.
It's simply to compare your drive signal to
You raise the AC signal either with more gain or less drain on that signal. the TS is a drain
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I'm thinking of introducing an optional circuit like this:
(https://i.postimg.cc/nzbm8pvd/Distorto-1.png)